var rt = new ReplSetTest( { name : "server_status_repl" , nodes: 2} );
rt.startSet();
rt.initiate();

rt.awaitSecondaryNodes();

var secondary = rt.getSecondary();
var primary = rt.getPrimary();
var testDB = primary.getDB("test");

assert.commandWorked(testDB.createCollection('a'));
assert.writeOK(testDB.b.insert({}, { writeConcern: { w: 2 }}));

var ss = primary.getDB("test").serverStatus({repl:1});
assert.neq(ss.repl.replicationProgress, null, tojson(ss.repl));

rt.stopSet();